In high bandwidth optical transport networks, recent standards such as ITU-T Recommendation G.709 “Interfaces for the optical transport network” (June 2016), the contents of which are incorporated by reference, describe the use of multiple optical carriers for a single digital transport interface in line side applications, such as an Optical Transport Unit-Cn (OTUCn) which is carried via multiple Optical Tributary Signal (OTSi) carriers (lambdas). For client side applications, ITU-T Recommendation G.709.1 (under progress) defines the use of multiple client services/modules for a single OTUCn transport service. Similarly, the Optical Internetworking Forum (OIF) has worked on IA # OIF-FLEXE-01.0 “Flex Ethernet Implementation Agreement” (March 2016), the contents of which are incorporated by reference, for FlexE to transport an Ethernet client service across multiple standard rate client interfaces/servers. The standards behavior is that upon a failure of any single carrier/module for the interface; the entire group is considered failed, and consequential actions are taken on the entire interface (or all services carried). As described herein, an interface is used for a network port and a service is used for individual services being carried within the interface. A single group interface can carry one or more services.
Of course, taking down the entire transport interface, although compliant to existing standards, can impact a significant amount of services. As services are deployed across multiple carriers/modules, the overall reliability (Failures in Time (FITS)/Mean Time Between Failures (MTBF)) is at risk. The components involved in the electro-optical interfaces typically have associated high failure rates. As an example, if the entire network interface is 600G and is being carried over four carriers, then a failure of a single carrier affects all 600G even though that single carrier may be responsible for only a quarter of that traffic (150G). Such lack of partial survivability has a major impact on the network in regard to failures. For failures, a network controller requires sufficient bandwidth to restore failed services. The lack of partial survivability significantly increases the amount of bandwidth, e.g., 600G instead of just 150G based on the aforementioned network interface example.